import React, { Component } from 'react'
// rcc
// react class component

/**
 * 生命周期
 * Mounting、Updating、Unmounting
 * 函数执行顺序
 * constructor、render(New props、setState、forceUpdate)、
 * React updates DOM and refs、componentDidMount、componentDidUpdate、componentWillUnmounting
 */
export default class App extends Component {
  render() {
    return 123
  }
}
